Recipe 4.11.
Generating a Unique Number
Problem
You want
to generate a unique number,
such as a number to append to a URL to prevent caching of the
URL.
Solution
Use the NumberUtilities.getUnique( )
method.
Discussion
Unique numbers are most commonly used to
generate a unique URL (to prevent it from being cached). That is,
by appending a unique number to the end of a URL, it is unlike any
previous URL; therefore, the browser obtains the data from the
remote server instead of the local cache.
The NumberUtilities.getUnique( ) method
returns a number based on the current epoch milliseconds. (The
following example assumes you've imported
ascb.util.NumberUtilities.)
// Display a unique number.
trace(NumberUtilities.getUnique( ));
In most circumstances the preceding code returns
the current epoch in milliseconds. However, it is possible that you
may want to generate a set of unique numbers in less than a
millisecond of processing time. In that case, you'll find that the
getUnique( ) method adds a random number to the epoch
milliseconds to ensure a unique number. The following example
generates more than one number within the same millisecond:
for(var i:Number = 0; i < 100; i++) {
trace(NumberUtilities.getUnique( ));
}
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